Photographic developing apparatus



nited states The invention relates to photographic processing apparatus, the term being widely used to include developing, washing, fixing, washing and drying in a comprehensive case, or merely developing, washing (or stop bath) and fixing in another procedure or any process involving the application of chemicals in solution to photographic material. Whilst the invention is applicable to negative processing, it is primarily intended for the processing of prints. In this latter context, the invention has several expected advantages including economy in reagents, the abilityto operate continuously, the ability to produce extremely uniform results, and to provide exact control of temperature and time, which in turn reduce the skill or attention required of the operator. The appaiatus gives development as even as that'commonly associated with prolonged immersion in very dilute solutions, combined with speed greater than that possible with manual agitation and dish development. In practice it has been found that the accuracy of timing combined with the variation of the speed of agitation gives a control of quality which is impractical by manual methods.

Apparatus according to the invention enables single prints or strips of prints to be developed in continuous succession, and experiment shows the advantage that a large number of prints can be developed of practically identical value and quality. This is a matter of considerable importance in commercial photography.

The invention will be discussed in its relation to prints, but it is to be understood that, subject to appropriate selection of reagents and time it is applicable to the de velopment of negatives on film, or with modification on plate, and to the processing of colour transparencies, colour negatives and prints.

The invention can make use, if desired, of a littleknown but effective developing process, which derives from a method of divided development attributed to G. H. Shipman as of 1893 and subsequently discussed in a not well-known book called Fawcetts Photography Handbook. By this process a first reagent is used containing the developer proper, the photograph is then subjected to the second (oxidiser) reagent whereupon it becomes visible. It is found that neither reagent suffers exhaustion except of course quantitatively, and that time, whilst being very rapid, is uncritical. First washing (or stop bath) fixing, washing, and drying, will follow and may or may not be provided for in our apparatus.

However, apparatus having features of the invention can be advantageously used with a conventional single agent.

The invention resides primarily in apparatus for the purpose described comprising conveyor means to convey photographs, a bath or baths through the liquid content of which the belt means moves immersed, and wiper means arranged to contact and move relatively to a photograph conveyed by the conveyor means in the bath so as to wipe the surface of the photograph whilst immersed. The wiper means preferably consist of brush-like elements arranged to move transversely to the direction of conveyor movement, preferably in oscillatory manner.

I In somewhat greater detail, the apparatus comprises a continuous belt arrangement of pliable material, inert to atent the reagents involved, and adapted to convey the photograph, guiding means over which the belt runs, driving means to move the conveyor continuously, means to wet the photograph whilst on the conveyor with the appropriate reagent or reagents, and water if washing is a stage (or a so-called short-stop reagent if to be used) and wiper means operating in conjunction with the conveyor arrangement to promote movement of the developer reagent and the others if required, evenly over the photograph and so that contact is constantly changed between photograph and reagent. This last means comprises, for example, a brush extending over the width of the conveyor arrangement and arranged to oscillate transversely to the motion of the conveyor. Or, it may comprise a roller with an absorbent surface, lightly rubbing the belt and carried photograph and running at a peripheral speed different from the belt speed. Or, it may be a roller having a helical brush or absorbent wiper, again running at a different speed. In the last case, the wiper may be laminations of soft rubber, analogous to the blade of a windscreen-wiper. In any of these cases, the contact means may be so made that the supply of developer or other reagent is metered through it, for example, through the hollow interior of the roller or spine of the brush.

A further feature is the provision of the conveyor arrangement, in the form of a plurality of parallel belts or filaments and these pass collectively over the rollers, contact means, etc., but at the terminal point where the photograph is to leave the belt, the roller has radially protruding flanges or rims which protrude between adjacentbelts and consequently ride the photograph olf the conveyor arrangement. Further, a pick-off roller may be provided just after this point, having projecting lugs or teeth (preferably "of soft rubber) which pass between the said flanges and, rotating in the same direction as the flanged roller, carry the photograph on to the next stage. In the case of a plural belt arrangement, an advantage is that the photograph, being well wetted on both sides and not trapping air beneath it, does not tend to cockle up.

Yet another feature resides in so arranging and constructing the device that it can be built in units, adapted to be assembled together or be placed in juxtaposition (and if desired having common driving means) each unit corresponding to one phase of the process. Thus, the first unit may effect the developing proper; this unit throws off the photograph, which passes straight into the second unit for fixing and this delivers to a washing bath. Between these two units there may be an arrangement of rollers, or a third complete unit, through which the photograph passes being subjected to a short-stopping reagent.

Preferably, the contacting means consists of a plurality of brushes arrayed across the conveyor arrangement where the latter passes through the reagent bath or pool, link mechanism causing the brushes to reciprocate alternately in opposite senses, i.e. out of phase; the net result is that there is no sideways drag tending to dislodge the belts or to work the photograph off sideways.

The motor or motors, whilst preferably electric, may be clockwork, or may be miniature hydraulic motors, driven, for example, by the flow of washing water.

Units adapted for mutual assembly may have shaft ends provided with couplings so that one unit is driven by its (powered) neighbour, and where the process requires that one step takes longer than another-the units being identical in themselves-gearing may provide for one to run faster than another.

Means may be provided to adjust the speed of running, so as to conform with the required time of processing and, perhaps, the rate at which prints are required to be fed in. The speed may also be governed by a t9 thermostatically-condolled heater incorporated into any bath where it may be of advantage.

The apparatus, at least that part of it carrying stillsensitive material, can conveniently be enclosed against light if required for other than darkroom use. Since it may be either simple, so as to perform only the developing operation, or more complex to result in finished dry photographs, or be between the two, it will be described by way of example in its most complete form.

An example of the invention is illustrated by the accompanying drawings, in which:

FIGURE 1 is a plan view (partly in section) of photographic developing apparatus having three baths in operational sequence;

FIGURE 2 is a sectional side elevation in diagram, of the apparatus shown in FIGURE 1; and

FIGURE 3 is a transverse cross section of the baths showing the construction of the side walls thereof.

The direction of running of the belts is in each case shown by the arrows associated with them.

A first bath 1 having parallel sides and inclined ends as shown is arranged at one end of a trough-like casing, having a floor 2 and end and side walls 3 and 4 respectively. On each side of the three baths there is provided an outer false wall 3a, provided to enclose and protect the mechanism and afford neat appearance, and also to form an inner false wall 3b providing bearings for some of the mechanism. These are of material such as plastic, or of protected metal, such as to be immune to attack by any reagent used; this choice of material applies to any other exposed parts of the apparatus so will not be referred to again.

Within the confines of this bath and supported mainly by a framework comprising the inner false walls 3b on appropriate bearings, is an idle roller 5; its bearings are slotted as shown at 6 so that tension springs 7 may keep the belt (to be described) in appropriate tension. The idle roller 5 is engaged by the belt means; this comprises a plurality of individual belt elements 8 which run in parallel in the arrow direction and are spaced apart. These elements 8 next (in their bath) pass below a second idle roller 9 (again borne in the frame wall 4) a third idle roller 19, a fourth idle roller 11, a fifth 12 and then over the belt driving roller 13. The roller 13 has pairs of flanges 14 at intervals in its length to correspond with and establish the lateral gap between the belt elements 3. These flanges 14 are of such radius that they are upstanding between the belts and they act to push up photographs from the collective belt elements 3, for transfer to the next belt system. The roller 13 is driven by driving belt (a chain may be substituted) 15, from a source to be described.

The belts 8 collectively, thence pass back under idle rollers 16, 17 underneath the bath 1 and again over the roller 5. Extending from over the roller 5, convergently to the immediate vicinity of roller 9, is a guide plate 18. It has been seen that the belt system, being led to and held downwardly by the rollers 9, 1G and 11 is so disposed as to pass immersed in the liquid content of the bath ll. In operation a photograph is fed in between the belts 8 and the roller 5 and the guide plate 18 and is carried down on the belt elements to be submerged in and passed through the reagent in the bath and then to be lifted clear of the reagent up the belt slope between the roller 11 and the roller 13, during which lifting it may drain surplus liquid back into the bath. The flanges 14 pick" the photograph off the belt elements for passage to the next bath.

Bushed in the walls 3b at 20 for sliding, is a rod 21. Upon this is mounted by lugs 22 between stops 23 a brush 24, having fairly long, pliant and reagent-immune bristles at 24A. The rod 21 is oscillated by a crank at 25 which is part of a crankshaft 26 driven by bevel wheels 27 from a motor drive-shaft 28. This same shaft 28 drives through spur reduction gears 29 a pulley shaft 30 carrying a pulley 31 which, through the belt 15, drives a pulley 32 on the spindle of the roller 13. It is clear that whenever the belt elements 8 are being driven the brush 24 will be oscillated transversely to the path of the belt. By this means a photograph being carried by the belt elements 8 is continuously and lightly brushed and wiped, this causing continuous agitation of the reagent in contact with the photograph and removing bubbles.

The brush 24 and its operating means is repeated as represented by the rods 21a throughout the operative length of the bath; it seems unnecessary to repeat the description thereof. In the drawn example there is a total of four brushes for the first bath 1. Their respective cranks may be phased at each from its neighhour.

In the simplest form of the invention, the apparatus described above could be complete in itself, but we prefer in practice to have a complete apparatus tofulfill the triple purpose of developing, washing and fixing so our description now carries on to the second bath in this three-bath integrated form.

The second bath shown at In is similar to the first bath 1, but is much shorter in length and is associated with an idle roller 33, supported in the same manner as the previously described idle rollers, supports second means comprising similarly constituted belt elements 34. These pass downwards beneath a guide bar 35 (for which an idle roller may be substituted) and thence upwards over driven roller 36 which is constructed with flanges, bearings, etc. just as is the roller 13. Thence the belting returns under idle roller 37 which is a tensioning roller supported in slots 38 and urged by springs 39. The spindle of the roller 36 is the spindle 30 previously mentioned.

It follows that the belting of this second bath 1a is driven simultaneously with that of the first bath; it may, however, be run at a faster linear speed according to the operational requirement. A reagent liquid is, of course, contained in the second bath. Photographs picked off the first belting are delivered over the gap indicated at 46 on to the second belting and thereby through the second bath.

The third bath lb is constituted and equipped in a manner so closely identical with the first bath 1 as to call for no detailed description. It is, however, to be observed that the tensioning means are, in this case, applied to the flanged roller 41 which is the final roller from which the photographs are discharged, passing in their exit over a small guide roller 43 shown in FIGURE 1. It is suggested that they be discharged directly so as to fall into a final washing tank which is no part of the invention. It will be clear that photographs picked off at roller 36 pass over the gap shown at 42 on their way from the second to the third bath.

As shown, the false walls 3a and 3b may constitute the vertical sides of inverted U-shaped members which, with or without a top covering member are hingedly connected at their ends to the trough-like casing 2, 3 and 4, so that when they are raised they will take up with them the rollers 9, 10, 11 and the brushes they carry, thus leaving the trays 1, 1a and 112 free to be lifted out for emptying, washing and clearing and refilling as may be required. To this end the inverted U-shaped members are hinged to the sides 4, 4 of the trough-like casing as indicated at 44 and 45. Preferably the inverted U-shaped members are made in half lengths so that their medial edges 47 butt on to each other where they can be secured in a straight line or closed position by means of a fastening such as a sliding bolt 46. Thus the turning up of the lefthand portion of the inverted U-shaped members will free the trays 1 and 1a, whilst the turning up of the right-hand portion of the inverted U-shaped members will free the tray 1b by taking up with it the rollers 9, 10, and 11 and the corresponding brushes. This operation simultaneously leaves the belts slack to permit the lifting out of the trays.

The ends of submerged spindles, such as those of rollers 9, and 11, for example, are sealed in their end bearings to prevent leakage of reagent from the baths; the other moving parts all being above or below the level in the baths, require no special provision against leakage. However, the slots 38 in the second bath are made, in effect, in the thickness of the side walls 3b.

The material of the belt elements should be not only pliable and appropriately immune from the reagents used, but also have a matt surface to avoid slipping of the photographs on them and to ensure the inclusion of liquid reagent between belting and the photograph. The photographs, assuming them to be paper prints, are usually and preferably run through with their sensitive sides upwards for direct action thereon of the brush wipers.

Although the invention has mainly been described in connection with processing apparatus for developing and washing prints in which flexible belts are used for conveying purposes, it will be obvious that a series of rollers may be used in the case of negatives mounted on rigid material such as glass or its equivalent.

From the foregoing it will be obvious that the invention includes separate individual baths with their adjuncts. If so applied, a series of baths can be arranged and re-arranged in any required serial conjunction and, by providing any appropriate shaft or belt couplers, can be operated from one driving motor such as that indicated at 48.

What we claim as new, and desire to secure by Letters Patent is:

1. Apparatus for the purpose described, comprising conveyor means to convey photographs, a bath through the liquid content of which the conveyor means moves immersed, and wiper means movable transversely to and in contact with a photograph conveyed by such conveyor means in the bath and including wipers movable out of phase with respect to each other to wipe the surface of the photograph whilst immersed.

2. Apparatus according to claim 1, in which the wipers are arranged in light contact with the photograph on the conveyor means.

3. Apparatus according to claim 2, in which said wipermoving means causes said wipers to oscillate across the path of the conveyor means.

4. Apparatus according to claim 2, in which each wiper comprises a bristled brush.

5. Apparatus according to claim 2, in which the conveyor means comprises a plurality of laterally spaced =belt elements moving together side by side at substantially the same speed and through paths which are substantially identical.

6. Apparatus according to claim 5, in which for the purpose of separating a photograph from the conveyor means the belt elements pass over a roller having projections which stand out between the bands.

7. Apparatus according to claim 2, in which there is common driving means for the conveyor means and the wiper means.

8. Apparatus according to claim 2, in which there is a series of baths each with its individual conveyor means at each except the last arranged to deliver photographs to the next.

9. Apparatus according to claim 2, including wiper means comprising elements mounted for oscillating sliding across the direction of the conveyor means and operated by a crankshaft.

10. Apparatus according to claim 8, in which the moving parts associated with each bath are driven from a common source.

References Cited in the file of this patent UNITED STATES PATENTS 1,055,121 Becker Mar. 4, 1913 1,633,216 Lakeman June 21, 1927 1,921,404 Crabtree Aug. 8, 1933 1,964,275 Secondo June 26, 1934 2,685,831 Strandberg Aug. 10, 1954 FOREIGN PATENTS 154,019 Germany Apr. 9, 1902 68,840 Austria May 25, 1915 745,616 Great Britain Feb. 29, 1956 

